PERANGKAT ANALOG ADMT4000 True Power On Multiturn Sensor
Circuits from the Lab® reference designs are engineered and tested for quick and easy system integration to help solve to-day’s analog, mixed-signal, and RF design challenges. For more information and/or support, visit www.analog.com/CN0602
Piranti disambungake / Referensi
ADMT4000 True Power-On Multiturn Sensor
LT3467 1.1A Step-Up DC/DC Converter with Integrated Soft-Start
EVALUASI LAN DUKUNGAN DESIGN
- Desain lan Integrasi Files
- Skema, Layout Files, Bill saka Material
FUNGSI SIRCUIT lan keuntungan
- This reference design provides a highly integrated development platform for the ADMT4000 true power‑on multiturn sensor in its thin shrink small outline package (TSSOP) package. Designed for easy prototyping and rapid evaluation, the board combines functionality, diagnostics, and modularity—eliminating the need for early-stage custom PCB layout. It allows designers to validate the ADMT4000 in conditions that closely mimic final production, including accurate pin mapping, signal integrity, thermal behavior, and packaging nuances. The board includes a plug‑and‑play interface featuring SPI connectivity and magnetic reset capability.
- The turn count sensor in the ADMT4000 is comprised of a spiral of giant magneto resistance (GMR) resistors, by which the magnetization pattern in these resistors is used to determine the turn count and the absolute position of a system. If the maximum
allowed magnetic field (BMAX) is exceeded, the GMR spiral may be corrupted. This scenario does not damage the device, but a reset of the spiral will be required. The reset can be achieved by rotating the system magnet more than 46 turns in the clockwise direction, or by applying a magnetic field greater than 60 mT in the 315° direction. Implementing the reset circuit with the specified components will ensure that the reset coil is energized sufficiently to generate the required magnetic field to reset the GMR turn count sensor. - Sirkuit sing ditampilake ing Figure 1 nyedhiyakake koil sing dibangun lan generator pulsa sing digunakake, ing kombinasi karo magnet sistem, kanggo ngreset sensor GMR.
Sirkuit kasusun saka blok kunci ing ngisor iki:
- Konfigurasi ADMT4000
- Pulse Generator kanggo GMR Magnetic Reset Coil
Gambar 1. Diagram Sirkuit Nggambarake Panggunaan Generator Pulse lan Koil kanggo Reset Magnetik Sensor GMR
Katrangan CIRCUIT
SPI INTERFACE
The ADMT4000 has an SPI interface, which can be used to control all the functions of the part and obtain the absolute position of a system on power-up. The general-purpose input/output (GPIO) pins are multifunctional pins and can be configured by setting a register to a specific function. For example, GPIO1 can be configured as an input, output, or convert start (CNV) pin.
Figure 2 shows the configuration when none of the GPIO pins are required. If the GPIO pins are not used, they should be tied to ground via a 100 kΩ resistor, except for GPIO5, which should be tied to VDRIVE via a 100 kΩ resistor.
Kaya sing digambarake ing Figure 3, resistor narik-mudhun ora dibutuhake nalika GPIO disambungake menyang mikroprosesor. 
Sirkuit ditampilake ing Figure 1 bisa diatur karo sembarang kombinasi GPIO digunakake utawa ora. Umume kasus, antarmuka SPI kudu disambungake langsung menyang mikroprosesor sing ana ing PCB sing padha. Nalika iku bisa kanggo drive antarmuka SPI liwat kabel, karakteristik kabel beda mbutuhake Filter RC. Cathetan sirkuit iki ora nemtokake nilai sing dibutuhake kanggo drive antarmuka SPI liwat kabel, nanging menehi jejak ing PCB kanggo nambah resistor lan kapasitor.
During normal operation, the ADMT4000 is typically connected directly to a microprocessor via the SPI interface. In this configuration, the resistors and capacitors identified by Note 1 on Figure 1 are not required. However, if the ADMT4000 is controlled by an off-board microprocessor, an RC filter may be necessary—de-pending on the characteristics of the connecting cable—to ensure reliable SPI communication. Additionally, the GPIO ports should be terminated in accordance with the guidelines provided in the ADMT4000 data sheet.
PULSE GENERATOR
Sirkuit generator pulsa kanggo kumparan reset dipérang dadi enem bagean utama:
- Voltage Sirkuit ngedongkrak
Voltage boost circuit based around the LT3467 step-up DC/DC converter is configured to boost the 5 V supply to 29.3
V. The converter charges the low ESR capacitor C12 to 29.3 V. - Watesan Saiki
Resistor R27 is used to control the inrush current to C12. If a power supply with a higher current rating is available, R27 can be reduced to shorten the capacitor’s charge time. - Sensing Saiki
While not required in the final application, a sense resistor R1 is included to allow measurement of the current pulse through the reset coil using a differential probe. - Reset Coil Configuration
The reset coil, L2, is a planar coil integrated into the PCB, see AN-2610 Application Note for further details of the coil layout. A reverse-biased diode, D2, is used across the integrated coil to provide a path for the inductive kickback from the coil. - Pulse Discharge Path
Kapasitor C12 dibuwang liwat L2 liwat saluran n MOSFET Q1. MOSFET dipilih kanggo low-on-resistance (Ron) karo low gate-source voltage (VGS). Although the chos-en MOSFET should be fully switched on at 3.3 V, it was found necessary to drive VGS at 5 V to give a reliable reset pulse. - Ground Noise Mitigation
Kanggo nyilikake gangguan lemah nalika discharge kapasitor, manik ferrite E1 digunakake kanggo misahake lemah reset coil saka liyane saka sirkuit.
VARIASI UMUM
Gumantung ing sumber kasedhiya voltages, the DC-DC converter used to charge the capacitor in the reset pulse generator may be modified. The CN0602 circuit uses an electrolytic capacitor with an ESR of 22 mΩ at 100 kHz. This capacitor can be replaced with a tantalum capacitor, provided its ESR remains within the same range.
EVALUASI SIRKUIT lan TES
The GMR turn count sensor can be reset by applying an external magnetic field with a field strength greater than 60 mT at the 315°orientation. A common method for generating this field is through the use of an electromagnet. In the CN0602 reference design, this is implemented using a wire coil positioned close to the sensor and embedded within the circuit board. A capacitor is used to charge and discharge through the coil, thereby producing the necessary magnetic field to reset the sensor.
Gambar 4 nampilake plot osiloskop saka sinyal kunci kanggo nggayuh sukses reset sensor count giliran GMR:
- Channel 1 displays the level-shifted 5 V coil reset signal.
- Channel 2 shows the original 3.3 V coil reset signal prior to buffering.
- Channel 3 illustrates the discharge of capacitor C12 through the coil to generate a strong magnetic field.
- Channel 4 captures the coil current, which peaks at nearly 200
- A. Saiki iki ngasilake medan magnet sing ngluwihi 60 mT ing orientasi 315 °, cukup kanggo ngreset sensor GMR.
Sinau luwih akeh
Paket Dhukungan Desain CN0602
SHEETS AND EVALUATION BOARDS
- ADMT4000 Data Sheet
- Lembar data LT3467
- Papan Evaluasi LT3467
RIWAYAT REVISI
8/2025—Revisi 0: Versi Awal
ESD Ati-ati
Piranti sensitif ESD (discharge elektrostatik). Piranti sing diisi daya lan papan sirkuit bisa dibuwang tanpa deteksi. Sanajan produk iki nduweni sirkuit perlindungan sing dipatenke utawa kepemilikan, bisa uga ana karusakan ing piranti sing kena ESD energi dhuwur. Mula, pancegahan ESD sing tepat kudu ditindakake kanggo ngindhari degradasi kinerja utawa ilang fungsi.
(Terus saka kaca pisanan) Sirkuit saka sirkuit Lab dimaksudaké mung kanggo nggunakake produk Piranti Analog lan minangka properti intelektual Piranti Analog utawa sing menehi lisensi. Nalika sampeyan bisa nggunakake Sirkuit saka sirkuit Lab ing desain produk, ora lisensi liyane diwenehake dening implikasi utawa digunakake ing sembarang paten utawa properti intelektual liyane dening aplikasi utawa nggunakake Circuit saka sirkuit Lab. Informasi sing diwenehake dening Piranti Analog dipercaya akurat lan dipercaya. Nanging, Sirkuit saka sirkuit Lab diwenehake "kaya" lan tanpa jaminan apa wae, eksplisit, tersirat, utawa statutoris kalebu, nanging ora diwatesi, garansi sing diwenehake babagan perdagangan, ora nglanggar utawa kabugaran kanggo tujuan tartamtu lan ora ana tanggung jawab sing ditindakake dening Piranti Analog kanggo panggunaane, utawa kanggo pelanggaran panggunaan paten utawa hak pihak katelu liyane. Piranti Analog duwe hak kanggo ngganti Sirkuit saka sirkuit Lab sawayah-wayah tanpa kabar nanging ora ana kewajiban kanggo nglakoni. Kabeh produk Piranti Analog sing ana ing kene tundhuk release lan kasedhiyan.
©2025 Analog Devices, Inc. Kabeh hak dilindhungi undhang-undhang. Merek dagang lan merek dagang kadhaptar minangka properti sing nduweni. One Analog Way, Wilmington, MA 01887-2356, USA
Dokumen / Sumber Daya
 |
PERANGKAT ANALOG ADMT4000 True Power On Multiturn Sensor [pdf] Instruksi Manual ADMT4000, ADMT4000 Daya Sejati Sensor Multiturn, ADMT4000, Daya Sejati Sensor Multiturn, Power On Multiturn Sensor, Sensor Multiturn, Sensor |